In recent years, along with widespread use of mobile phones, mobile phone base stations are being installed in places all over the world. For connection of a mobile phone network, it is necessary to construct a network for connecting the mobile phone base stations to each other. When a wired network is used as the network for connecting the mobile phone base stations to each other, enormous construction cost is required, and hence a wireless network is often used globally. In this wireless network, one-to-one communication is normally established, and hence a reflector antenna capable of achieving a high gain in one direction is used.
As a conventional reflector antenna, Japanese Unexamined Patent Application Publication (JP-A) No. 2009-17346 (hereinafter referred to as “Patent Literature 1”) discloses the following reflector antenna 160. Specifically, as illustrated in FIG. 16, electromagnetic waves from a primary radiator 161 reflect off a sub-reflecting mirror 162 to enter a main reflecting mirror 163. The reflector antenna 160 of this type includes the plurality of reflecting mirrors 162, 163, and hence is called a dual reflector antenna. The sub-reflecting mirror 162 is closely supported on a dielectric support member 164 mounted to a tip of the primary radiator 161.